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User Manual
Airbridge cBTS3612 CDMA Base Station
CPU
l
The CPU is in charge of the control of BTRM, which includes the initialization upon
power-on, alarm collecting and reporting, and processing operation & maintenance
related messages.
Power supply
l
With input voltage of +27V, the power supply sub-unit provides power supply to
BIFU and BRCU.
2) BTS Radio up-down Converter Unit (BRCU)
BRCU consists of transmitter, main/diversity receiver and local oscillator. It
up-converts, amplifies the intermediate frequency signals output by BIFU, and
performs spuriousness-suppression wave filtering. It also performs analog
down-conversion, amplification of BTS main/diversity receiving signal input from the
RLDU, and channel-selection wave filtering. The functions of each sub-unit are as
below．
Transmitter
l
When receiving the modulated analog intermediate frequency signals output by
BIFU, the transmitter converts them to specified RF band via two times of
up-conversions. Before and after the up-conversion, wave filtering, signal
amplification and power control are performed, so as to ensure the RF signals
output meet the protocol requirements on power level, Adjacent Channel Power
Radio (ACPR) and spuriousness.
Main/diversity receiver
l
It converts the RF signals output by RLDU to specified intermediate frequency
signals via down-conversion, and performs wave filtering, signal amplification and
power control before/after the down-conversion, so as to ensure the intermediate
frequency signals output can be received by BIFU.
Local oscillator
l
It consists of the intermediate frequency source and transmit/receive RF synthesizer.
The intermediate frequency source generates the local frequency signals for
intermediate frequency up-conversion in transmit path. The RF synthesizer
generates the local frequency signals for the up-conversion of the transmit path and
the local frequency signals for the down-conversion of main/diversity receive path.
II. Interface
There
descriptions of each interface are given as below:
are
interfaces
between
BTRM
and
BHPA/ RLDU/BRDM/PSU.
2-27
System Description
2 Hardware Architecture
The
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